Saturday, January 16, 2016

A Hierarchical-Triple System of Brown Dwarfs

VHS 1256-1257 is a hierarchical-triple system whose three components are all substellar in nature. This means all three components are below the minimum mass needed to sustain hydrogen fusion to shine as stars. In VHS 1256-1257, the “A” and “B” components are being orbited by the more distant “b” component.If VHS 1256-1257 is assumed to be ~41 light years away, then the “A” and “B” components each have ~64.6 times the mass of Jupiter and orbit one another every 5.87 ± 2.7 years, while the more distant “b” component has ~11.2 times the mass of Jupiter. If the system is assumed to be ~56 light years away, then the “A” and “B” components each have ~73 times the mass of Jupiter and orbit one another every 8.7 ± 4.3 years, while the “b” component has ~35 times the mass of JupiterThe configuration of VHS 1256-1257 resembles hierarchical-triple star systems. This suggests VHS 1256-1257 formed via the extension of the star formation process down to lower masses. VHS 1256-1257 is the third known triple system whose components are all substellar in nature.Reference:Stone et al. (2016), “Adaptive Optics imaging of VHS 1256-1257: A Low Mass Companion to a Brown Dwarf Binary System”, arXiv:1601.03377 [astro-ph.SR]